FIG. 1 shows a coordinate system for explaining a conventional method for decelerating a motor vehicle. The conventional method for decelerating a motor vehicle is described in DE 10 2011 103 936 A1, for example.
In the coordinate system in FIG. 1, the abscissa is a time axis t (in seconds). The ordinate of the coordinate system in FIG. 1 depicts a wheel braking torque M (as the sum of both wheel braking torques of an axle) in newton meters.
A deceleration of the motor vehicle is requested at a point in time t=0. As a response to the braking request, a brake pressure buildup is begun in at least one wheel brake cylinder at a front axle of the motor vehicle. The brake pressure buildup in the at least one wheel brake cylinder of the front axle, up to a friction braking torque Mhyd effectuated by the at least one wheel brake cylinder of the front axle, is equal to the braking request, but requires a comparatively long time (approximately 700 ms). For this reason, beginning at a (communication-related) reaction time Δt0, an electric motor which is designed for decelerating the motor vehicle is also controlled in such a way that the electric motor (immediately) effectuates a motor braking torque Mm for decelerating the motor vehicle. In the conventional method for decelerating a motor vehicle, the electric motor is controlled in such a way that effectuated motor braking torque Mm remains less than or equal to a limiting motor braking torque Mm0, above which a load on the electric motor exceeds the nominal load capacity (nominal load).
Due to the joint use of the at least one wheel brake cylinder of the front axle and the electric motor which is designed for decelerating the motor vehicle, the aim is to be able to effectuate a total braking torque Mtotal (as the sum of friction braking torque Mhyd and motor braking torque Mm) which already exerts a braking effect on the motor vehicle immediately after reaction time Δt0 has elapsed. In particular, the aim is for a braking distance of the motor vehicle that is to be decelerated to be reducible with the aid of the method depicted in FIG. 1.